Screen resolution refers to the clarity of the text and images on your screen. At higher resolutions, items appear sharper. They also appear smaller, so more items fit on the screen. At lower resolutions, fewer items fit on the screen, but they are larger and easier to see. At very low resolutions, however, images might have jagged edges.
For example, 640 × 480 is a lower screen resolution, and 1600 × 1200 is a higher one. CRT monitors generally display a resolution of 800 × 600 or 1024 × 768. LCD monitors can better support the higher resolutions. Whether you can increase your screen resolution depends on the size and capability of your monitor and the type of video card you have.